With the advancement of science and technology, fluid control devices are widely used in many sectors such as pharmaceutical industries, computer techniques, printing industries or energy industries. Moreover, the fluid control devices are developed toward elaboration and miniaturization. The fluid control devices are important components that are used in for example micro pumps, micro atomizers, printheads or industrial printers for transporting fluid. Therefore, it is important to provide an improved structure of the fluid control device.
FIG. 1A is a schematic cross-sectional view illustrating a portion of a conventional fluid control device. FIG. 1B is a schematic cross-sectional view illustrating an assembling shift condition of the conventional fluid control device. The main components of the conventional fluid control device 100 comprise a substrate 101 and a piezoelectric actuator 102. The substrate 101 and the piezoelectric actuator 102 are stacked on each other, assembled by any well known assembling means such as adhesive, and separated from each other by a gap 103. In an ideal situation, the gap 103 is maintained at a specified depth. More particularly, the gap 103 specifies the interval between an alignment central portion of the substrate 101 and a neighborhood of a central aperture of the piezoelectric actuator 102. In response to an applied voltage, the piezoelectric actuator 102 is subjected to deformation and a fluid is driven to flow through various chambers of the fluid control device 100. In such way, the purpose of transporting the fluid is achieved.
The piezoelectric actuator 102 and the substrate 101 of the fluid control device 100 are both flat-plate structures with certain rigidities. Thus, it is difficult to precisely align these two flat-plate structures to make the specified gap 103 and maintain it. If the gap 103 was not maintained in the specified depth, an assembling error would occur. Further explanation is exemplified as below. Referring to FIG. 1B, the piezoelectric actuator 102 is inclined at an angle θ by one side as a pivot. Most regions of the piezoelectric actuator 102 deviate from the expected horizontal position by an offset, and the offset of each point of the regions is correlated positively with its parallel distance to the pivot. In other words, slight deflection can cause a certain amount of deviation. As shown in FIG. 1B, one indicated region of the piezoelectric actuator 102 deviates from the standard by d while another indicated region can deviate by d′. As the fluid control device is developed toward miniaturization, miniature components are adopted. Consequently, the difficulty of maintaining the specified depth of the gap 103 has increased. The failure of maintaining the depth of the gap 103 causes several problems. For example, if the gap 103 is increased by d′, the fluid transportation efficiency is reduced. On the other hand, if the gap 103 is decreased by d′, the distance of the gap 103 is shortened and is unable to prevent the piezoelectric actuator 102 is from readily being contacted or interfered by other components during operation. Under this circumstance, noise is generated, and the performance of the fluid control device is reduced.
Since the piezoelectric actuator 102 and the substrate 101 of the fluid control device 100 are flat-plate structures with certain rigidities, it is difficult to precisely align these two flat-plate structures. Especially when the sizes of the components are gradually decreased, the difficulty of precisely aligning the miniature components is largely enhanced. Under this circumstance, the performance of transferring the fluid is deteriorated, and the unpleasant noise is generated.
Therefore, there is a need of providing an improved fluid control device in order to eliminate the above drawbacks.